Portable oxygen generating systems have been used to provide oxygen in a variety of circumstances, including medical emergencies, athletic events, and high altitude activities. Portable oxygen may be used to supplement normal breathing in these circumstances, or to provide life-saving oxygen in cases of injury. Because portable oxygen systems are often the only means available to generate an adequate supply of oxygen, it is important for such devices to provide a high flow rate of breathable oxygen over an extended period of time. To this end, for example, the U.S. Food and Drug Administration requires that in order for an oxygen generating apparatus to be sold without a prescription, it must provide an average of at least six liters of oxygen per minute for fifteen minutes.
Known oxygen generating systems often require a user to mix a number of chemicals in a vessel and then add water after the chemicals are mixed. These systems typically cannot produce the FDA-required flow of oxygen because of human error in mixing the reagents or because the reagents react too quickly or too slowly. Likewise, other known systems that provide the reagents in a cartridge format often produce too little oxygen over too short a period of time, because the reagents are not provided in a manner that effectively regulates the reaction. In addition, the exothermic reaction which produces the oxygen also tends to overheat reaction vessels and provide oxygen at uncomfortable temperatures, further decreasing the effectiveness of known oxygen generating units.